Metal-Organic Gel Leading to Customized Magnetic-Coupling Engineering in Carbon Aerogels for Excellent Radar Stealth and Thermal Insulation Performances.

Metal-organic gel (MOG) derived composites are promising multi-functional materials due to their alterable composition, identifiable chemical homogeneity, tunable shape, and porous structure. Herein, stable metal-organic hydrogels are prepared by regulating the complexation effect, solution polarity and curing speed. Meanwhile, collagen peptide is used to facilitate the fabrication of a porous aerogel with excellent physical properties as well as the homogeneous dispersion of magnetic particles during calcination. Subsequently, two kinds of heterometallic magnetic coupling systems are obtained through the application of Kirkendall effect. FeCo/nitrogen-doped carbon (NC) aerogel demonstrates an ultra-strong microwave absorption of - 85 dB at an ultra-low loading of 5%. After reducing the time taken by atom shifting, a FeCo/Fe3O4/NC aerogel containing virus-shaped particles is obtained, which achieves an ultra-broad absorption of 7.44 GHz at an ultra-thin thickness of 1.59 mm due to the coupling effect offered by dual-soft-magnetic particles. Furthermore, both aerogels show excellent thermal insulation property, and their outstanding radar stealth performances in J-20 aircraft are confirmed by computer simulation technology. The formation mechanism of MOG is also discussed along with the thermal insulation and electromagnetic wave absorption mechanism of the aerogels, which will enable the development and application of novel and lightweight stealth coatings.

Fabrication of Hollow Cube Dual-Semiconductor Ln2O3/MnO/C Nanocomposites with Excellent Microwave Absorption Performance.

Metal-organic frameworks (MOFs) have been verified as ideal precursors for preparing highly effective microwave absorbers. However, it is still challenging to fabricate a thin, lightweight, and well-organized nanostructure with strong microwave absorption (MA) capability and wide absorption bandwidth. In this study, hollow cube dual-semiconductor Ln2O3/MnO/C (Ln = Nd, Gd, Er) nanocomposites, which are effective microwave absorbers, have been fabricated via one-step high-temperature carbonization of Ln-Mn-MOFs. The effect of band gap on the MA performance of various nanocomposites synthesized at the same carbonization temperature is investigated. Gd2O3/MnO/C-800 shows superior MA capacity with maximum reflection loss (RLmax) of -64.4 dB at 12.8 GHz and 1.86 mm-thickness. When the thickness is 1.44 mm, the RL value is obtained as -52.7 dB at 16.8 GHz, and at a low frequency of 4.36 GHz and thickness of 4.59 mm, the RL value reaches -56.4 dB. Further, the effect of temperature on the MA properties of Gd2O3/MnO/C is examined. The results reveal that Gd2O3/MnO/C-700 has an ultrahigh MA bandwidth of 6.6 GHz, covering the entire Ku bands at 2.09 mm-thickness. Overall, this work demonstrates a facile strategy to construct hollow, homogeneous ternary composites with outstanding MA performance.

Antifungal activities of anthocyanins from purple sweet potato in the presence of food preservatives.

Effects of anthocyanins from purple sweet potato (APSP) against the fungal growth of Geotrichum candidum and Candida albicans were assessed. Response surface methodology was applied for optimization of proportions of sodium benzoate, potassium sorbate, and APSP. Optimum concentrations against G. candidum were 0.300 mg/mL of sodium benzoate, 0.290mg/mL of potassium sorbate, and 13.9mg/mL of APSP. Optimum concentrations against C. albicans were 0.380 mg/mL of sodium benzoate, 0.240 mg/mL of potassium sorbate, and 3.56 mg/mL of APSP. APSP exhibited enhanced antifungal properties in the presence of food preservatives.

Randomized-controlled phase II clinical trial of a bacterially expressed recombinant hepatitis E vaccine.

The candidate recombinant hepatitis E vaccine, HEV 239, protect monkeys against infection by hepatitis E virus (HEV). The safety and immunogenicity of the vaccine for humans was assessed in a randomized controlled phase II clinical trial. The study was conducted in an endemic area of southern China and consisted of a dose scheduling, involving 457 adults and a dose escalation component involving 155 high school students. The results showed that the vaccine is safe and immunogenic for humans and suggest that it could prevent new HEV infection.

Poly[µ-5-ammonio-isophthalato-aqua-µ-oxalato-dysprosium(III)].

The title complex, [Dy(C(8)H(6)NO(4))(C(2)O(4))(H(2)O)](n), is a dysprosium coordination polymer with mixed anions and was obtained under hydrothermal conditions. In the structure, the oxalate and 5-amino-isophthalate ligands link the dysprosium ions, building up a two-dimensional metal-organic framework parallel to the (10) plane. These sheets are further connected through O-H⋯O, N-H⋯O and C-H⋯O hydrogen bonds, forming a three-dimensional supra-molecular structure.

catena-Poly[[[tetra-aqua-cobalt(II)]-µ-4,4'-bipyridine-κN:N'] 2-[4-(2-carboxyl-ato-eth-yl)phen-oxy]acetate].

In the title complex, {[Co(C(10)H(8)N(2))(H(2)O)(4)](C(11)H(10)O(5))}(n), the unique Co(II) ion lies on an inversion center and is coordinated by two N atoms from two 4,4'-bipyridine ligands and four O atoms from four water mol-ecules in a slightly distorted octa-hedral coordination geometry. The 4,4'-bipyridine ligands bridge Co(II) ions into a one-dimensional chain structure. In the crystal structure, inter-molecular O-H⋯O hydrogen bonds link cations and anions into a three-dimensional network. The dianions are completely disordered about an inversion center.

2-(2-Hydroxyphenyl)-4,5-dimethyl-1H-imidazol-3-ium acetate monohydrate.

In the title compound, C(11)H(13)N(2)O(+)·C(2)H(3)O(2) (-)·H(2)O, the dihedral angle between the benzene ring and the imidazole ring is 7.83 (6)°. In the crystal structure, N-H⋯O and O-H⋯O hydrogen bonds form a two-dimensional network. All the methyl H atoms are disorderd over two sites with equal occupancies.

6-Bromo-3-hydr-oxy-4-oxo-2-phenyl-4H-chromene-8-carboxylic acid dimethyl-formamide disolvate.

In the title compound, C(16)H(9)BrO(5)·2C(3)H(7)NO, the chromene ring system is essentially planar. The two dimethyl-formamide solvent mol-ecules are linked by inter-molecular O-H⋯O hydrogen bonds to the 6-bromo-3-hydr-oxy-4-oxo-2-phenyl-4H-chromene-8-carboxylic acid molecules.

Tetrakis[µ-3-(3-pyridyl)acrylato-κO:O']bis{(1,10-phenanthroline-κN,N')[3-(3-pyridyl)acrylato-κO,O']europium(III)} pentahydrate.

The europium(III) ion in the title compound, [Eu(2)(C(8)H(6)NO(2))(6)(C(12)H(8)N(2))(2)]·5H(2)O, is coordinated by seven carboxyl-ate O atoms and two N atoms from one phenanthroline mol-ecule. The carboxyl-ate groups of 3-(3-pyrid-yl)acrylate link pairs of europium(III) ions, forming centrosymmetric dinuclear units, which further assemble into a sheet parallel to the (001) plane through hydrogen-bonding inter-actions involving the uncoordinated water mol-ecules. One water molecule is disordered.

2,3:6,7-Bis(methyl-enedi-oxy)-phenanthrene.

In the title mol-ecule, C(16)H(10)O(4), all the non-H atoms are coplanar. The crystal structure is stabilized by weak inter-molecular C-H⋯O contacts and π-π stacking inter-actions (the inter-planar distance is 3.43 Å).

3,5-Dibromo-2-hydroxy-benzoic acid.

The title compound, C(7)H(4)Br(2)O(3), has an intra-molecular O-H⋯O=C hydrogen bond and aggregates to form hydrogen-bonded dimers via O-H⋯O inter-actions. The formation of zigzag one-dimensional mol-ecular tapes via C-H⋯Br inter-actions and π-π stacking inter-actions (inter-planar separation = 3.42 Å) completes the crystal structure.